EP-A-2 607 636 discloses an example of cam follower, comprising a tappet, a pin and a roller. The tappet extends along a longitudinal axis, while the pin and the roller are centered on a transverse axis. The tappet is formed with two lateral flanges, delimiting an intermediate gap between them and each comprising a cylindrical bore. The roller is positioned in the intermediate gap, between both flanges and bores. The pin is fitted in the two bores, such that the roller is movable in rotation relative to the pin around its axis. The pin is then caulked, in other words plastically deformed, on both opposite ends to create a mechanical connection by press-fit in the tappet bores.
When the cam follower is in service, the roller collaborates with a cam synchronized with the internal combustion engine camshaft. The rotation of the camshaft leads to a periodic displacement of a piston of the pump that rests against the tappet, to allow fuel to be delivered. The tappet is movable back and forth along the longitudinal axis, while the roller is movable in rotation around its central axis.
In EP-A-2 607 636, the caulking operation allows to retain the pin along the transverse axis. The roller is positioned in the tappet, then the pin is inserted through the bores and the roller. Finally, the pin ends are caulked by press-fit in the bores. Thus, the pin is secured relative to the tappet, both in rotation and in translation.
Alternatively, it is known to implement caulking on the tappet, such that the pin is partly movable relative to this tappet. The pin can rotate around the transverse axis. Besides, the pin can move on a small distance along the transverse axis, but cannot be removed from the tappet.
However, caulking processes are difficult to control and require powerful machines.
JP-A-2013/029027 discloses another example of cam follower. The tappet comprises two flanges including holes for receiving the end of the pin. However, due to their particular shapes, the flanges are difficult to mold. Moreover, due to limited access for the tool, the holes are difficult to shape by machining. Moreover, the flanges must be deformed in order to insert the pin into the holes.